JP2583398B2 - Ultrasonic welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic bonding apparatus for bonding, for example, a metal as a member to be bonded by ultrasonic vibration.

[0002]

2. Description of the Related Art Conventionally, an ultrasonic bonding apparatus for bonding metal as a member to be bonded, for example, with metal by ultrasonic vibration is well known, for example, from Japanese Patent Publication No. 54-23349. The ultrasonic bonding apparatus according to the above publication comprises an elongated resonator having a length of at least one wavelength at a predetermined frequency of ultrasonic waves and providing three antinode regions of longitudinal movement at resonance, A processing member engaging tip that engages with the processing member is provided in one of the belly regions. Each of the other two antinode regions in the resonator is connected to a support via a pair of support members.

[0003] In the resonator connected to the supporting member via the pair of supporting members, the processing member is pressed to come into contact with the processing member engaging tip to apply a pressing force substantially perpendicular to the ultrasonic vibration direction. The members to be joined are joined by giving.

In an ultrasonic oscillator for applying ultrasonic vibration to the resonator, an amplitude is applied at a two-stage oscillation start as shown in FIG.

[0005]

By the way, in the conventional ultrasonic bonding apparatus described above, the resonator is mounted on a pair of support members made of a pair of metal sheets at the two antinode regions of the resonator, that is, at the point of maximum vibration amplitude. Since it is supported, there is a problem that the energy loss of the ultrasonic wave at the time of joining is large, the variation of the joining is large, and the number of defective products is increased, and the reliability of the device itself is deteriorated.

Further, in the conventional ultrasonic oscillator, the amplitude is given to the resonator by the two-stage oscillation start, so that the starting stress is 300 to 500% of the running stress as shown in FIG. Thus, there is a problem that it can cope with a small load or a small output, but cannot cope with other cases.

An object of the present invention is to provide an ultrasonic bonding apparatus that reduces the energy loss of ultrasonic waves during bonding, improves the reliability of the apparatus itself, and widens the range of use of bonding. .

[0008]

In order to achieve the above object, an ultrasonic bonding apparatus according to the present invention has a length of at least one wavelength of a predetermined frequency of an ultrasonic wave, and at least at the time of resonance at the frequency. Ultrasonic horn (27) having three points of maximum vibration amplitude in the longitudinal direction at both ends and the center
At the maximum vibration amplitude point at the center of the ultrasonic horn (27), protruding outside the ultrasonic horn (27),
₁ , W ₂ ) and coaxially connected to the maximum vibration amplitude points at both ends of the ultrasonic horn (27), and have a length of a half wavelength of the ultrasonic frequency. A booster (25, 29) having a maximum vibration amplitude point at both ends thereof and a nodal point at the center thereof;
An ultrasonic vibrator (23) coaxially connected to one (25) of one of the boosters (25, 29), and a supporting member (19R) in which a nodal point in each of the boosters (25, 29) is clamped by mechanical clamping means. , 19L) and, these support members (19R, 19L) and the bonded members (W _1, W ₂₎
A cradle (5) to be joined member and caused to relatively move (W _1, W ₂₎ occupies applying pressure to said engaging tip (31) to the pressurizing means for mounting the, in that it comprises It is a feature.

In the ultrasonic bonding apparatus (1), an ultrasonic oscillator (22) capable of performing a linear ramp variable soft start is provided by the ultrasonic vibrator (2).
3), wherein the mechanical clamping means comprises a projection (25) integrally formed with a width centered on the nodal point of each booster (25, 29).
F, 29F) directly to the support member (19R, 19L)
And the clamping member (37R, 37L) is adapted to be strongly clamped, and the pedestal (5) is fixed.
Move the L) is intended, it is desirable that consists of bonded members (W _1, W ₂₎ occupies applying pressure engagement tip (31) to the pressing cylinder (7).

[0010]

With [action] above-described ultrasonic bonding apparatus (1), placing the workpieces (W _1, W ₂₎ consisting of, for example, metal and metal on the cradle (5). Then, the ultrasonic electric signal supplied from the ultrasonic oscillator (22) is converted into mechanical vibration by the ultrasonic vibrator (23). The mechanical vibration is transmitted to the ultrasonic horn (27) and the other booster (29) through the booster (25), and is transmitted to the booster (2).
5, 29) and the ultrasonic horn (27) are vibrated in the horizontal direction.

The support members (19R, 19L) on which the boosters (25, 29) are supported are moved in a direction orthogonal to the vibration direction by, for example, a pressurizing means, so that the engaging tips (27) are arranged on the ultrasonic horn (27). 31) to the members to be joined (W ₁ , W
Ultrasonic bonding is performed by contacting with ₂ ) and applying vibration while applying pressure. At this time, each booster (25, 2
9) The supporting member (19R, 1) at the nodal point
9L), the adherence of the material to be welded (W ₁ , W ₂ ) and the ultrasonic horn (27) can be suppressed as much as possible at the time of joining, so that the ultrasonic horn (2
7) The service life is extended, the energy loss of ultrasonic waves is reduced, and the reliability of the device itself is improved, so that the range of use of bonding is expanded.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIG. 1, the ultrasonic bonding apparatus 1 includes, for example, a box-shaped main body frame 3, and the main body frame 3 includes a lower frame 3D and side frames 3R, 3R.
L and the upper frame 3U. A receiving table 5 on which the members W ₁ and W ₂ are placed is provided on the lower frame 3D.

At the lower part of the upper frame 3U, a cylinder base 9 having, for example, a pressure cylinder 7 as a pressure means is mounted. A gate-shaped support frame 15 is fixed to a tip of a piston rod 11 mounted on the pressurizing cylinder 7 with a plurality of screws 13.

A support 1 is provided below the support frame 15.
7 are integrated, and support members 19R and 19L are integrated below the support 17. On the lower surface of the cylinder base 9 and the upper surface of the support 17, for example, a plurality of tension springs 21 as an elastic machine are attached. Holes or notches 3H are formed in lower portions of the side frames 3R and 3L.

An ultrasonic oscillator 23 is connected to the ultrasonic oscillator 22, and a booster 25 is connected to the ultrasonic oscillator 23 as well shown in FIGS. An ultrasonic horn 27 is connected to the booster 25, and another booster 29 is connected to the ultrasonic horn 27. Further, the engaging tip 31 that engages the workpieces W ₂ in the lower portion of the ultrasonic horn 27 is provided.

The structure of the ultrasonic oscillator 22 is shown in FIGS.
The linear ramp variable soft start having the performance shown in FIG. For details of the linear ramp variable soft start, see U.S.A. S. As described in P4, 277, 710, it can be understood by referring to the above publication if necessary.

Each of the boosters 25 and 29 has a convex portion 25 cut to a width centered on a nodal point described later.
F, 29F are formed. These projections 25F, 29F
Are mechanically and strongly clamped directly to the metal supporting members 19R and 19F. For example, as shown in FIG. 2, stepped holes 33R, 33L are formed in support members 19R, 19L.
Are formed, and a female screw 35 is formed on the inner peripheral surface of the large-diameter portion of each of the stepped holes 33R and 33L. In addition, the boosters 25 and 29 are inserted into the stepped holes 33R and 33L, and external threads 39 are formed on the outer peripheral surfaces of the metal fastening members 37R and 37L.

With the above configuration, the support members 19R, 19L
By screwing the male screw 39 of the tightening members 37R and 37L into the female screw 35 of the
The nine protrusions 25F, 29F are firmly clamped to the support members 19R, 19L.

The ultrasonic electric signal (pulse) of the ultrasonic oscillator 22 is converted into mechanical vibration by the ultrasonic vibrator 23. This mechanical vibration causes linear ramps as shown in FIGS.
Driven by a variable soft start, this mechanical vibration is transmitted to the ultrasonic horn 27 and the other booster 29 through the booster 25 as shown in FIG.

The wavelength of the ultrasonic wave transmitted to the booster 25, the ultrasonic horn 27, and the booster 29 is such that the ultrasonic horn 27 has a maximum vibration amplitude point at both ends and a center and a minimum stress. That is, the length is set in advance to a length corresponding to one wavelength of the frequency of the ultrasonic wave. Also,
The convex portions 25F, 29F of the boosters 25, 29 are preset so as to have a zero point of vibration amplitude (called a nodal point) and to have a maximum stress.

As described above, the wavelength of the ultrasonic wave is set in advance, and the convex portions 25F, 29F of the boosters 25, 29 are mechanically and strongly clamped to the supporting members 19R, 19L. In this state, for example, a metal is placed on the receiving table 5 as the members to be joined W ₁ and W ₂ , and the booster 2
5, while applying the ultrasonic vibration to the ultrasonic horn 27 and the booster 29 in the longitudinal direction of the ultrasonic horn 27, that is, in the left-right direction in FIG. 3, the pressurizing cylinder 7 is operated to extend the piston rod 11 downward. Frame 1
5, the support 17 and the support member 19R, booster 25 through 19L, the ultrasonic horn 27 and the booster 29 is moved downward, the engaging tip 31 is first in contact with the metal W _2, metal and further moved downward Pressure is applied to W ₂ and W ₁ .

Then, between the contact surfaces of the metal W ₁ and the metal W ₂ , the oxide film covering the surfaces of the metals W ₁ and W ₂ is broken and an activated metal surface appears. Furthermore, since the temperature rise at the boundary at the boundary due to friction is added, the distance between the active atoms is reduced and metal bonding is performed. After metal joining is performed, the piston rod 11 is contracted and the tension spring 2
With the spring force of 1, the booster 25, the ultrasonic horn 27 and the booster 29 are raised and returned to their original positions.

Therefore, the connecting portion between both ends of the ultrasonic horn 27 and the boosters 25 and 29 is set at the maximum vibration amplitude point of the wavelength,
By setting the minimum stress point and setting the flanges 25F and 29F of the boosters 25 and 29 supported by the supporting members 19R and 19L to the zero point (nodal point) of the vibration amplitude of the wavelength and the maximum stress point, joining is performed at the time of joining. Members W ₁ , W ₂
Therefore, the life of the ultrasonic horn 27 is extended and the energy loss of ultrasonic waves can be reduced as much as possible. As a result, models with lower power levels can be used. In addition, complex applications and large power bonding can be put to practical use. In addition, there is no variation in bonding and no defective products are generated, so that the reliability of the device itself is improved as compared with the related art, and the range of use of bonding can be expanded.

In the present embodiment, the members W ₁ and W ₂ can be joined not only between the same kind of metal but also between different kinds of metal. In particular, it is suitable for joining materials such as copper and aluminum, and is also capable of joining aluminum and ceramics. Although the ultrasonic transducer 23 converts an electric signal into mechanical vibration, the ultrasonic transducer 23 has an electrostrictive type P.
When ZT ceramics are used, the conversion efficiency can be 95% or more.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[0027]

As will be understood from the embodiments described above, according to the present invention, the members to be joined (W ₁ , W
₂ ) Adhesion between the ultrasonic horn (27) and the ultrasonic horn (27) can be suppressed as much as possible, so that the life of the ultrasonic horn (27) can be extended, and further, the energy loss of the ultrasonic wave can be reduced as much as possible. As a result, models with lower power levels can be used. In addition, complex applications and large power bonding can be put to practical use. In addition, there is no variation in bonding, and no defective products are generated, so that the reliability of the apparatus itself can be improved as compared with the related art and the range of use of ultrasonic bonding can be expanded.

[Brief description of the drawings]

FIG. 1 is a front sectional view of an ultrasonic bonding apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged detailed view of a portion viewed from an arrow II in FIG. 1;

FIG. 3 is an explanatory diagram showing a relationship between ultrasonic vibrations, an ultrasonic horn, and a booster according to the present invention.

FIG. 4 is a diagram showing a relationship between time and amplitude in an ultrasonic oscillator capable of performing a linear ramp variable soft start.

FIG. 5 is a diagram showing a relationship between time and running stress in an ultrasonic oscillator capable of performing a linear ramp variable soft start.

FIG. 6 is a diagram showing a relationship between time and amplitude in a conventional ultrasonic oscillator.

FIG. 7 is a diagram showing a relationship between time and running stress in a conventional ultrasonic oscillator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ultrasonic bonding apparatus 5 Cradle 7 Pressurizing cylinder (pressurizing means) 19R, 19L Support member 21 Tension spring (elastic machine) 22 Ultrasonic oscillator 23 Ultrasonic oscillator 25, 29 Booster 25F, 29F Convex part 27 Ultrasonic Horn 31 Engagement tip W ₁ , W ₂ Workpiece

Claims (4)

(57) [Claims] An ultrasonic horn having a length of at least one wavelength of a predetermined frequency of ultrasonic waves and having three maximum vibration amplitude points in a longitudinal direction at least at both ends and a center at resonance at the frequency. 27) and the ultrasonic horn (2) at the maximum vibration amplitude point at the center of the ultrasonic horn (27).
And the bonded member projecting outwardly of 7) (W _1, W ₂₎ and engages the engaging tip (31), said ultrasonic horn (27)
A booster (2) which is coaxially connected to the maximum vibration amplitude points at both ends of the booster and has a half-wave length of the frequency of the ultrasonic wave, and has a maximum vibration amplitude point at both ends and a nodal point at the center.
5, 29) and an ultrasonic transducer (23) coaxially connected to one (25) of these boosters (25, 29).
And support members (19R, 19L) in which the nodal points in the boosters (25, 29) are clamped by mechanical clamping means, and these support members (19R, 1R).
9 L) and the bonded members (W _1, W ₂₎ was placed cradle (5) and the relative movement allowed by the workpieces (W _1, W
₂ ) An ultrasonic bonding apparatus, further comprising a pressurizing means for pressurizing the engaging tip (31). 2. A linear ramp variable software system.
An ultrasonic oscillator (22) that can be started
The ultrasonic bonding device according to claim 1, wherein the ultrasonic bonding device (23) is connected to the ultrasonic vibrator (23). 3. The mechanical clamping means includes a projection (25F, 29F) integrally formed with a width around a nodal point in each booster (25, 29).
2. The ultrasonic bonding apparatus according to claim 1, wherein the ultrasonic bonding apparatus is configured to be directly clamped to the supporting member (19R, 19L) by a fastening member (37R, 37L). 4. A fixing the cradle (5), the pressurizing means said supporting member (19R, 19L) engaging tip (31) to the workpieces by moving (W _1, W ₂₎ 2. An ultrasonic bonding apparatus according to claim 1, wherein said ultrasonic bonding apparatus comprises a pressurizing cylinder for pressurizing.